FAQs ABOUT FELINE IMMUNODEFICIENCY VIRUS (FIV)
What is FIV?
FIV stand for feline immunodeficiency virus. It is a lentivirus, the same class of virus as HIV. FIV, which can live in many different tissues in cats, typically causes a weakening of the cat's immune system.
How do cats get FIV?
One of the tissues in which FIV lives is the salivary glands, so the most common route of infection is a deep bite wound from a FIV-positive cat to another cat. It can also be transmitted via blood, in utero and from milk from an infected mother cat. It is very rare for cats to get FIV from just being around infected cats, from sharing food bowls, or from a person touching a FIV-positive cat and then touching a FIV-negative cat.
What are the signs of FIV infection?
There are no specific signs of FIV infection. FIV-positive cats have a weaker immune system so they are more prone to getting infections such as upper respiratory infections, ringworm and dental disease. Other than that, FIV-positive cats tend to live normal lives and have a normal length of life.
How do I know if my cat has FIV?
There are no obvious signs of FIV so the only way to know is to do a blood test. The most common screening test is an ELISA test (often called a SNAP test) done by your veterinarian, which looks for antibodies to FIV. An antibody is a protein made by the cat in response to FIV infection. A cat can test positive as soon as two to four weeks after exposure, but it can take up to eight weeks. Kittens under six months of age may test positive after having received antibodies from their mothers, either in utero or via milk. It can take up to six months for these antibodies to go away. Thus, it is a good idea to retest a kitten who tests positive after he or she has reached six months of age.
Can FIV be treated?
There are no proven treatments to rid a cat of FIV. Most FIV-positive cats handle the disease well, but it is important to concentrate on treating the secondary illnesses.
What can be done to prevent the spread of FIV?
Cats should be kept indoors so they do not fight with a FIV-positive cat. Depending on where one lives, the rate of FIV-positive cats ranges from 4 to 24 percent. A FIV-positive cat can live with a FIV-negative cat as long as neither cat is a fighter, or the FIV-positive cat has no teeth. (FIV-positive cats commonly have severe dental disease, which often means it is necessary to remove all their teeth.)
There is a vaccine for FIV, but the vaccine does not have the best efficacy and, after a cat is vaccinated for FIV, the cat will test positive for the virus. At this point, no test can differentiate whether a cat tests positive for FIV from the vaccine or from having the infection. If a cat escapes and is picked up by local animal control and then tested, the cat may be killed because he or she tests positive.
Can FIV-negative and FIV-positive cats live together?
Yes, as long as the cats get along and do not fight. The risk that a FIV-positive cat could spread the virus to a FIV-negative cat can be minimized by having them live in separate rooms until you are confident that they will not fight with each other.
Can FIV-positive cats have a good and long life?
FIV-positive cats can live normal lives both in quality and duration. They do take special care in terms of monitoring them for signs of infection and they do have a tendency to have bad dental disease.
Feline Leukemia Virus
What is feline leukemia virus?
Feline leukemia virus (FeLV) is a retrovirus, so named because of the way it behaves within infected cells. All retroviruses, including feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV), produce an enzyme which permits them to insert copies of their own genetic material into that of the cells they have infected. Although related, FeLV and FIV differ in many ways, including their shape: FeLV is more circular while FIV is elongated. The two viruses are also quite different genetically and their protein constituents are dissimilar in size and composition. Although many of the diseases caused by FeLV and FIV are similar, the specific ways in which they are caused differs.
How common is the infection?
FeLV-infected cats are found worldwide, but the prevalence of infection varies greatly depending on their age, health, environment and lifestyle. In the United States, approximately 2 to 3% of all cats are infected with FeLV. Rates rise significantly - 13% or more - in cats who are ill, very young, or otherwise at high risk of infection.
How is FeLV spread?
Cats persistently infected with FeLV serve as sources of infection. Virus is shed in very high quantities in saliva and nasal secretions, but also in urine, feces and milk from infected cats. Cat-to-cat transfer of virus may occur from a bite wound, during mutual grooming, and (though rarely) through the shared use of litter boxes and feeding dishes. Transmission can also take place from an infected mother cat to her kittens, either before they are born or while they are nursing. FeLV doesn't survive long outside a cat's body - probably less than a few hours under normal household conditions.
What cats are at greatest risk of infection?
Cats at greatest risk of infection are those who may be exposed to infected cats, either via prolonged close contact or through bite wounds. Such cats include:
- Cats living with infected cats or with cats of unknown infection status;
- Cats allowed outdoors unsupervised, where they may be bitten by an infected cat; and
- Kittens born to infected mothers.
Kittens are much more susceptible to infection than are adult cats and therefore are at the greatest risk of infection if exposed. But accompanying their progression to maturity is an increasing resistance to FeLV infection. For example, the degree of virus exposure sufficient to infect 100% of young kittens will infect only 30% or fewer adults. Nonetheless, even healthy adult cats can become infected if sufficiently exposed.
What does FeLV do to a cat?
Feline leukemia virus adversely affects the cat's body in many ways. It is the most common cause of cancer in cats, it may cause various blood disorders and it may lead to a state of immune deficiency that hinders the cat's ability to protect itself against other infections. The same bacteria, viruses, protozoa and fungi that may be found in the everyday environment - where they usually do not affect healthy animals - can cause severe illness in those with weakened immune systems. These secondary infections are responsible for many of the diseases associated with FeLV.
What are the signs of disease caused by FeLV?
During the early stages of infection, it is common for cats to exhibit no signs of disease at all. However, over time - weeks, months, or even years - the cat's health may progressively deteriorate or be characterized by recurrent illness interspersed with periods of relative health. Signs can include:
I understand there are two stages of FeLV infection. What are they?
FeLV is present in the blood (a condition called viremia) during two different stages of infection:
- Primary viremia, an early stage of virus infection. During this stage some cats are able to mount an effective immune response, eliminate the virus from the bloodstream and halt progression to the secondary viremia stage.
- Secondary viremia, a later stage characterized by persistent infection of the bone marrow and other tissue. If FeLV infection progresses to this stage, it has passed a point of no return; the overwhelming majority of cats with secondary viremia will be infected for the remainder of their lives.
How is infection diagnosed?
Two types of FeLV blood tests are in common use. Both detect a protein component of the virus as it circulates in the bloodstream.
Each testing method has strengths and weaknesses. Your veterinarian will likely suggest an ELISA-type test first, but in some cases, both tests must be performed - and perhaps repeated - to clarify a cat's true infection status.
How can I keep my cat from becoming infected?
The only sure way to protect cats is to prevent their exposure to FeLV-infected cats.
- Keep cats indoors, away from potentially-infected cats who might bite them. If you do allow your cats outdoor access, provide supervision or place them in a secure enclosure to prevent wandering and fighting.
- Adopt only infection-free cats into households with uninfected cats.
- House infection-free cats separately from infected cats and don't allow infected cats to share food and water bowls or litter boxes with uninfected cats.
- Consider FeLV vaccination of uninfected cats. (FeLV vaccination of infected cats is not beneficial.) Discuss the advantages and disadvantages of vaccination with your veterinarian. FeLV vaccines are widely available, but since not all vaccinated cats will be protected, preventing exposure remains important even for vaccinated pets. FeLV vaccines will not cause cats to receive false positive results on ELISA, IFA or any other available FeLV tests.
I just discovered that one of my cats has FeLV. I have other cats as well. What should I do?
Unfortunately, many FeLV-infected cats are not diagnosed until after they have lived with other cats. In such cases, all other cats in the household should be tested for FeLV. Ideally, infected and non-infected cats should then be separated to eliminate the potential for FeLV transmission.